Setting max packet size (Interrupt) to 64 bytes

- 128 bytes is invalid for USB 2.0 Full-Speed (max 64 bytes)

Output/pjrcUSB/arm/usb_desc.h

@@ -66,7 +66,7 @@
 
 #define NKRO_KEYBOARD_INTERFACE 1 // NKRO Keyboard
 #define NKRO_KEYBOARD_ENDPOINT  2
-#define NKRO_KEYBOARD_SIZE      128
+#define NKRO_KEYBOARD_SIZE      64
 #define NKRO_KEYBOARD_INTERVAL  1
 
 #define CDC_IAD_DESCRIPTOR      1

Output/pjrcUSB/avr/usb_keyboard_serial.h

@@ -203,7 +203,7 @@ int8_t usb_serial_set_control(uint8_t signals); // set DSR, DCD, RI, etc
 
 #define KEYBOARD_NKRO_INTERFACE  0
 #define KEYBOARD_NKRO_ENDPOINT   1
-#define KEYBOARD_NKRO_SIZE       128
+#define KEYBOARD_NKRO_SIZE       64
 #define KEYBOARD_NKRO_HID_BUFFER EP_DOUBLE_BUFFER
 
 #define KEYBOARD_INTERFACE       1